Organic electroluminescent elements have advantages such as self-emission and high-speed response and are expected to find application in flat panel displays. In particular, ever since a report about a two-layer type (laminated type) in which a hole transporting organic thin film (hole transport layer) and an electron transporting organic thin film (electron transport layer) are laminated, [this type] has been of increasing interest as a large surface area light-emitting element that emits light at a low voltage of 10 V or less. A laminated-type organic electroluminescent element has a basic structure comprising a positive electrode, a hole transport layer, a light-emitting layer, an electron transport layer, and a negative electrode.
Organic electroluminescent elements such as this have been the subject of various investigations because they afford high luminous efficiency.
For example, with an organic electroluminescent element including an electron transport layer, a hole transport layer, an anode, and a cathode, an element has been proposed which further includes (a) a hole blocking layer that is disposed between the cathode and the electron transport layer and that has a greater ionization potential than the ionization potential of the electron transport layer and/or (b) an electron blocking layer that is disposed between the anode and the hole transport layer and that has less electron affinity than the electron affinity of the hole transport layer (Patent Document 1). There have been attempts at using this element configuration to increase the reverse bias characteristics of the element and to improve the brightness and luminous efficiency.